Q upgrade - fixup completion messages and --help doctext
Q upgrade - fixup completion messages and --help doctext

This fixes a nit in the upgrade prepare completion message and
adds missing completion messages for run and converge. I also
added missing doctext - it is useful as it is what the operator
sees with --help

Change-Id: Ia5bc8abaf2d04bd829df85d9a4b2a8a913271af8

openstack/python-tripleoclient